$padding:20px;
$width:600px;
$height:300px;
body{
    padding: $padding;
}
#container{
    position: relative;
     width: $width;
     height: $height;
     border: 3px solid #333;
     overflow: hidden;
}
#list{
    $width:4200px;
    position: absolute;
    z-index: 1;
    width: $width;
    height: $height;
    img{
        float: left;
        width: 600px;
        height: $height;
    }
}

#buttons{
    position: absolute;
    left: 250px;
    bottom:$padding;
    z-index: 2;
    height: 10px;
    width: 100px;
    span{
        float: left;
        margin-right: 5px;
        width: 10px;
        height: 10px;
        border: 1px solid #fff;
        border-radius: 50%;
        background: #333;
        cursor: pointer;
    }
}
#buttons .on{
    background: orangered;
}
.arrow{
    position: absolute;
    top: 100px;
    z-index: 2;
    display: none;
    width: 40px;
    height: 40px;
    font-size: 36px;
    font-weight: bold;
    line-height: 36px;
    text-align: center;
    color: #FFFFFF;
    background-color: rgba(0,0,0,.3);
    cursor: pointer;
    &:hover{
        background-color: rgba(0,0,0,.7);
    }
}
#container:hover .arrow{
    display: block;
}
#prev{
    left: 20px;
    
}

#next{
    right: 20px;
}
